Line S12 is a

S-Bahn The S-Bahn is the name of hybrid urban- suburban rail systems serving a metropolitan region in German-speaking countries. Some of the larger S-Bahn systems provide service similar to rapid transit systems, while smaller ones often resemble co ...

line of the S-Bahn Köln network in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

. It is operated by

DB Regio DB Regio AG is a subsidiary of Deutsche Bahn which operates regional and commuter train services in Germany. DB Regio AG, headquartered in Frankfurt am Main. It is a 100% subsidiary of the Deutsche Bahn Group and there part of the DB Regio bus ...

using class 423 electric multiple units. The S12 runs from

Horrem Kerpen (; Ripuarian: ''Kerpe'') is the most populated town in the Rhein-Erft-Kreis (North Rhine-Westphalia, Germany). It is located about 20 kilometres southwest from Cologne. Division of the town The town of Kerpen was created in 1975, whe ...

via

Cologne Cologne ( ; german: Köln ; ksh, Kölle ) is the largest city of the German western States of Germany, state of North Rhine-Westphalia (NRW) and the List of cities in Germany by population, fourth-most populous city of Germany with 1.1 m ...

to Au (Sieg). It shares this route for most of its run with the S 19. With over , it is the second longest S-Bahn line in North Rhine-Westphalia, after S9. The S12 operates every 20 minutes on workdays between Köln Ehrenfeld and Hennef (Sieg), with every third train continuing to Au (Sieg). The S19 also operates hourly between Au (Sieg) and Hennef, so there is a 30 minute clock. During rush hour, the S12 gets extended to Horrem, so with the S19 six trains operate hourly in each direction between Cologne and Horrem. Services operates every 20 minutes on Saturdays and every 30 minutes on Sundays and public holidays. On Sundays and public holidays the S12 operates every 30 minutes between Horrem and Au (Sieg). The route runs on the Cologne–Aachen line (opened by the

Rhenish Railway Company The Rhenish Railway Company (German language, German: ''Rheinische Eisenbahn-Gesellschaft'', RhE) was along with the Cologne-Minden Railway Company (CME) and the Bergisch-Märkische Railway Company (BME) one of the railway companies that in the m ...

between Cologne and Horrem in three stages between 1839 and 1841), the

East Rhine Railway The East Rhine Railway (German: ''Rechte Rheinstrecke'', literally 'right (of the) Rhine railway') is a major, double-track, electrified railway line, running along the right bank of the Rhine from Cologne to Wiesbaden. The -long line forms two De ...

(opened to Troisdorf by the Rhenish Railway in 1870, with an extension to Cologne opened in 1874) and the

Sieg Railway The Sieg Railway (german: Siegstrecke is a long, electrified Rail transport in Germany, German main line railway between Köln Messe/Deutz station, Cologne-Deutz via Porz (Rhein) station, Porz, Troisdorf railway station, Troisdorf, Siegburg/Bonn s ...

(opened by the

Cologne-Minden Railway Company The Cologne-Minden Railway Company (German, old spelling: ''Cöln-Mindener Eisenbahn-Gesellschaft'', ''CME'') was along with the Bergisch-Märkische Railway Company and the Rhenish Railway Company one of the railway companies that in the mid-19th ...

between 1859 and 1862). The eastern section of the S 12 service from Au (Sieg) to

Köln-Nippes Nippes (; ) is the fifth borough (') of Cologne, Germany. Nippes was incorporated into the city of Cologne in 1888 and the district was created in 1975. A large Ford Europe production plant is located in Niehl, the north-eastern part of the dist ...

was opened on 2 June 1991. It was extended to Düren on 13 June 2004, dropping Köln-Nippes. It was cut back to Horrem in December 2015.

References

{{Reflist Rhine-Ruhr S-Bahn 1991 establishments in Germany